Electrical cord accessory



April 25, 1967 G. J. TRANGMAR ELECTRICAL CORD ACCESSORY Filed Nov. 20,1964 3,316,523 ELECTRICAL CORD ACCESSORY George J. Trangmar, 418 S.Shaffer, Orange, Calif. 92666 Filed Nov. 20, 1964, Ser. No. 412,734 3Claims. (Cl. 339-75) The present invention relates to an accessory foruse in cooperation with an electrical plug of the type employed totemporarily establish electrical connection between a source ofpower anda utilization apparatus.

Electrically powered hand tools have now come into exceedinglywidespread use. For example, in the construction industry, a vast numberof electrically-powered hand saws are used by carpenters. Of course, inusing electrical hand tools, they must be connected, as by a cord, to asource of electrical power. Conventionally, several lengths of cord,each terminating in a plug or terminal connector, are available for usewith a hand tool. The user then interconnects the required number ofthese cords to permit use of the hand tool at the desired location.

One of the problems in using hand tools in the construction industry,and in related fields as well, is that the plugs or terminal structurestend to catch on virtually any obstacle with the result that the usermust frequently stop working, trace the cord to the location where theplug is caught and free the plug for further movement. Of course, thisoperation is time consuming and annoying to the user of the electricalhand tool or other apparatus.

Another problem attendant the use of portable electrical hand tools isthat the cord or power line frequently parts, thereby requiring repair.Most usually, the line separation involves simply a pair of plugs orjunction terminals that have been pulled apart. However, notinfrequently, the break occurs in the cord or power line, the mostfrequent instance of which is a break contiguous a plug.

As a result of these difficulties arising in the use of electricallypowered hand tools, a need exists for an accesory which may be combinedwith an electrical plug and cord, in combination, to permit the use ofthese hand tools with greater effectiveness and convenience.Furthermore, the accessory of the present invention is also useful incooperative combination with electrical plugs employed in conjunctionwith various other forms of electrical apparatus and equipment.

An object of the present invention is to provide an accessory for use incombination with an electrical plug and cord, which reinforces the plugand cord against separation, provides a smooth transitional surfacebetween the plug and the cord to avoid the junctions from catching onvarious obstacles, and incorporates fastening means whereby pairs of thecombination units may be locked together.

Another object of the present invention is to provide an accessory foruse in combination with an electrical plug and cord, which accessory maybe inexpensively manufactured, and effectively employed in conjunctionwith said plug and cord combination.

A further object of the present invention is to provide an improvedjunction in an electrical cord or transmission line utilized forconnecting an electrical apparatus to a source of electrical energy.

These and other objects and advantages of the present invention willbecome apparent from a consideration of nited States Patent 3,316,523Patented Apr. 25, 1967 the following, taken in conjunction with thedrawing, wherein:

FIGURE 1 is a perspective view of a combination structure incorporatingthe present invention;

FIGURE 2 is a vertical sectional view taken along line 2-2 of FIGURE 1;

FIGURE 3 is a vertical sectional view taken along line 3-3 of FIGURE 1;

FIGURE 4 is a perspective view of a component of the combinationstructure of FIGURE 1;

FIGURE 5 is a sectional view of another form of accessory incorporatingthe principles of the present invention;

FIGURE 6 is a vertical sectional view taken along line 6-6 of FIGURE 5;and

FIGURE 7 is a perspective view of a component incorporated in thestructure of FIGURE 5.

Referring initially to FIGURE 1, there is shown a flat cylindrical plug10 as well known and widely used in conjunction with electrical handtools. The plug 10 incorporates a set of electrical prongs 12 serving asjunction terminals and friction fasteners. An electrical cord 14incorporating individual conductors 16 is aflixed to the plug 10 withthe conductors 16 electrically contacting the prongs 12. An accessory 18constructed in accordance with the present invention is thencooperatively mated with the plug 10 and the cord 14 as a result ofbeing fixed over the cord 14 contiguous the rear of the plug 10.

In function, the accessory 18 provides a conical configuration, theoutside surface of which afiords a smooth contiguous surface between theplug 10 and the cord 14. As a result, the plug 10 may be easily pulledacross various obstacles without catching thereon. Furthermore, theaccessory 18 serves to reinforce the attachment between the plug 10 andthe cord 14, as well as relieving the strain normally received by thecord 14 contiguous the plug 10.

Considering the structure of the present invention in greater detail,reference will now be had, somewhat simultaneously to FIGURES 1, 2, 3and 4. The accessory 18 consists of two separate sections 20 and 22(FIGURE 3) joined by a pair of self-threading screws 24 and 26;, set inrecesses 28 and 36 in the section 20.

The two sections 20 and 22 mate to form the conical configuration of theaccessory and also to define a particular interior cavity. That is, thesections 20 and 22 each contain interior chambers defining a coaxialpassage through the accessory through which the cord 14 passes andfurther providing irregularities serving to fix the accessory to theplug 10. Specifically, a semi-cylindrical cavity 32 (FIGURE 4) entersthe small end 34 (remote the plug 10) extending substantially half-waythrough the section. At the termination of the cavity 32, a largersemi-cylindrical cavity 36 is formed in each of the sections 20 and 22provided to receive a flange clamp 38 (FIGURE 2) which is a portion ofthe plug it and serves to clamp the plug 10 to the cord 14. The cavity36 is partially closed by a semi-annular end 40 (FIGURE 4) defining anopening 42.

In mating relationship, the sections 20 and 22 provide a passage definedby the cavities 32 which receives the cord 14. These cavities are linedby teeth 44 which bite into the cord 14 so that the strains applied tothe cord 14 are transferred to the plug 10 through the accessory 18rather than through the electrical junction between the .cord 14 and theplug 10.

Adjacent the passage defined by the cavities 34 in the accessory 18 is alarger chamber defined by the cavities 36 serving to contain the clamp38. The ends 40 of the two sections 20 and 22 dwell in the space 48between the clamp 38 and the plug 10 in the assembled configurationlocking the accessory to the plug 10. Therefore, the accessory 18 islocked to the plug 10 by the ends 40 and to the cord 14 by the teeth 44.

The accessory structure as shown in FIGURES 1 through 4 may be bestmanufactured of insulating material, thereby avoiding exposed surfaceswhich may be energized by electrical potential. For example, thesections 20 and 22 may be molded of plastic, hard rubber, or variousother similar materials. In this regard, the teeth 44 may be molded intothe surface of the cavity 32 comprising the same material as theremainder of the section; or, alternatively, the teeth 44 may beprovided in a. cylindrical metal liner or separately-embedded teeth maybe used.

In using the accessory, it is a simple matter to bring the sections 20and 22 into mating relationship locked over the clamp 38. Thereafter,the screws 24 and 26 are easily placed in the sections 20 and 22fastening them together so that the accessory may be parted if desiredat a later time. In this regard, the clamp 38 will normally be tightenedby tightening the bolts 46 comprising a part thereof prior to applyingthe accessory 18. Thereafter, the accessory 18 provides shelter for thebolts 46 with the result that they are less likely to be loosened, inturn releasing the clamp 38.

In certain instances, a modified form of the accessory embodimentconsidered above will be found useful. One example of such a modifiedform will now be considered with reference to FIGURES 5, 6 and 7 whereinelements similar to those previously described carry identical referencenumbers. FIGURE shows a male plug as previously considered matablyengaged with a female plug 50 having an exterior configuration similarthe plug 10. The plug 50 carries a clamp 52 incorporating bolts 54 forlocking the plug 50 to a cord 56. As shown in FIGURE 5, the plugs 10 and50 are both equipped with accessories 58 which units are locked togetherby a spring leaf 60 as shown in FIGURE 7. As a result,- the plugs 10 and50 may not be easily separted without first releasing the spring leaf60. Therefore, in pulling the cords 14 and 56 through and over variousobstacles, the

' plugs 10 and 50 are not easily separated.

Considering the structure of FIGURE 5 in greater detail, the twoaccessories 58 as shown are identical in form, comprising an uppersection 62 and a lower section 64 held together in mating relationshipby a snap ring 66 positioned in an annular groove 68' about the sections62 and 64. The mated sections 62 .and 64 define a concentric cylindricalpassage 70 bearing teeth 72 which lock the accessory 58 to the cordlying in the passage 70.

The passage 70, adjacent the small end of the accessory 58 opens into alarger cavity 74 which is partially closed by the annular end 76dwelling in the space 48 7 between the clamp of the plug and the plugproper to lock the accessory to the plug.

The cavity '74 is generally cylindrical and receives a large transversebore 78 and a small rectangular-section transverse passage 80. Thepassages 80 carry the ends of the spring leaf 60 anchoring two plugse.g. plugs '10 and 50 in mating relationship. The spring leaf '60 (FIG-URE 7) includes an elongate flat section 82 the ends 84 and 86 of whichare turned substantially normal to the section 82. The terminations 88and 90 of the ends 84 and 86 respectively, are again curved to providelocking flaps.

The accessories 58 as shown in FIGURES 5 and 6 may be formed of sectionswhich are molded or otherwise formed of various insulating materials,e.g. plastics, or hard rubber. The spring leaf 60 may be formed bystamping or various other operations and will normally be made of metale.g. beryllium copper or spring steel.

In assembling the structure as shown in FIGURE 5, the plugs 10 and 50are first mated respectively to the cords 14 and 56. Thereafter, thebolts 46 and 54 are tightened thereby clamping the plugs onto theirassociated cords. Next, the sections 62 and 70 of the accessories 58 aremated over the plugs 10 and 50 along with the cords 14 and 56, andlocked in position by placement of the snap rings 66, which structuresare very well known in the prior art.

Next, the plugs 10 and 50 are matingly engaged and the spring leaf 60 ispositioned with one end in each of the passages 80, so that the tabs 88and extend along the interior of the cavity 74 locking the spring leafin position to hold the plugs 10 and 50 in mating relationship.

In using the structural combination as illustrated in FIGURE 5, it canbe appreciated that the provision of a smooth continuous surface betweenthe cords 14 and 56 permits the junction therebetween to be pulled overvarious obstacles without being caught thereon. Furthermore, theinterlocking relationship between the two accessories 58 preserves theplugs 10 and S0 mated together with relatively few occurrences of plugseparations.

Still further, it is also apparent that mechanical stresses applied tothe cords 14 and 56 are largely relieved by the accessories 58 ratherthan to be applied to the electrical junction. As a result, failureoccurs less frequently.

At the conclusion of a particular job, it may be desired to separate theplugs 10 and 50 as shown in FIG- URE 5. To accomplish such separation,the operator inserts a finger through the bores 78 contacting one of theend tabs 88 or 90 urging it toward the plugs 10 and 50 so that it isreleased and may be withdrawn through the passage 80. As a result, thetwo plugs 10 and 50 are no longer locked together and may be easilydisconnected. Of course, if it should be necessary to repair one of theplugs or otherwise gain access thereto, it is readily apparent that theaccessories 58 are easily parted by simply removing the snap ring 68 bytwisting the ends 92 thereof as shown in FIGURE 6.

As apparent from the above consideration, the structure of the presentinvention provides an advantageous accessory which may be simply andeasily manufactured in large quantity, and which affords considerableconvenience and time saving in the use of power tools supplied withelectrical energy through extended lengths of electrical cord. Ofcourse, other advantages and features of the present invention inaddition to those apparent from the embodiment described herein will bereadily understood and appreciated by persons skilled'in the art.Furthermore, various modifications of the embodiments shown anddescribed herein will also be apparent. Therefore, the scope hereofshall not be determined by the disclosure set forth above, but rather bythe claims appended hereto.

What is claimed is:

1. In combination:

a first electrical plug including a spaced-apart transversely-extendingcord clamp defining an indentation;

a first electrical cord afiixed to said first electrical plug by saidcord clamp;

a second electrical plug to mate with said first electrical plug, alsoincluding a spaced-apart transverselyextending cord clamp defining anindentation;

a second electrical cord affixed to said second electrical plug by saidcord clamp;

first and second accessories for each of said first and second plugs,each of said accessories including;

first and second sections of insulating material 5 a 6 matable to definea conical exterior configurament with said accessories and accessiblefor release ration, said sections each further defining inbeneath theexterior configuration of said accessories. ternal chambers to receivesaid cord and internal extensions to matingly engage said plugReferences Cited y the Examine! inaaid indentatlion, by liocking1engagement with 5 U D STATES PATENTS sai transverse y-exten rng c amp;an means for locking said first and second sections Nerf) 339-403 XWhite 229-63 In mating relationship affixed to said plug and 2 043 6666/1936 Ki b 339 63 said cord whereby to provide a smoothly tapered2841635 7/1958 iz I 339 75 transitional surface between said plug andsaid 10 3170749 2/1965 J 1 e I cord o anson et a 2. A combinationaccording to claim 1 further com- FOREIGN PATENTS prising fasteningmeans for locking said first and said second accessories togetherwhereby to hold said first and 1,098,645 3/1955 Francesecond plugsmatingly engaged. 15

3. A combination according to claim 2 wherein said EDWARD ALLEN PrimaryExaminer fastening means includes latching portions for engage- W.DONALD MILLER, Examiner.

1. IN COMBINATION: A FIRST ELECTRICAL PLUG INCLUDING A SPACED-APARTTRANSVERSELY-EXTENDING CORD CLAMP DEFINING AN INDENTATION; A FIRSTELECTRICAL CORD AFFIXED TO SAID FIRST ELECTRICAL PLUG BY SAID CORDCLAMP; A SECOND ELECTRICAL PLUG TO MATE WITH SAID FIRST ELECTRICAL PLUG,ALSO INCLUDING A SPACED-APART TRANSVERSELYEXTENDING CORD CLAMP DEFININGAN INDENTATION; A SECOND ELECTRICAL CORD AFFIXED TO SAID SECONDELECTRICAL PLUG BY SAID CORD CLAMP; FIRST AND SECOND ACCESSORIES FOREACH OF SAID FIRST AND SECOND PLUGS, EACH OF SAID ACCESSORIES INCLUDING;FIRST AND SECOND SECTIONS OF INSULATING MATERIAL MATABLE TO DEFINE ACONICAL EXTERIOR CONFIGURARATION, SAID SECTIONS EACH FURTHER DEFININGINTERNAL CHAMBERS TO RECEIVE SAID CORD AND INTERNAL EXTENSIONS TOMATINGLY ENGAGE SAID PLUG IN SAID INDENTATION, BY LOCKING ENGAGEMENTWITH SAID TRANSVERSELY-EXTENDING CLAMP; AND MEANS FOR LOCKING SAID FIRSTAND SECOND SECTIONS IN MATING RELATIONSHIP AFFIXED TO SAID PLUG AND SAIDCORD WHEREBY TO PROVIDE A SMOOTHLY TAPERED TRANSITIONAL SURFACE BETWEENSAID PLUG AND SAID CORD.